Importance

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Abstract

All of the current processes for making molded particleboard products require very long furnish dwell times within a heated press, due to the low heat transfer rates from the heated molds to the furnish being compressed. Furnish dwell times vary between approximately one minute to more than 10 minutes, depending upon the part thickness. Since profitability of a particleboard molding operation is closely related to product throughput, these long furnish dwell times within the heated press limit production rates and continue to be a major economic concern to the industry. The essence of the invention is a heretofore unsuggested use of radiowave energy to speed production of molded particleboard parts by preheating the furnish prior to the application of heat and pressure within the forming mold. Because radiowaves propagate readily throughout the volume of the furnish, rapid heating is obtainable even for a loose, uncompacted particulate furnish that has very poor thermal conductivity. By utilizing a radiowave preheating scheme, rather than applying radiowaves simultaneously with hot pressing, relatively simple yet highly effective radiowave applicators may be devised.

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First Claim